This application is just working very well and is very useful.
I am for the moment working on version 2011a and will soon update to 2013. Do you know if any update will be done in order to be compatible with this version ? (To avoid to loose my work...)
Anyway, great job !
Sorry for the delay -- somehow I missed your question.
Yes, you can show only folders by entering '^' as the regular expression filter. That will cause the program to display only files that begin with nothing. Since no file has no name and folders are exempt from RE filtering (by default), only folders will be displayed.
I realize that's a bit of a hack so I will consider adding such a feature.